« Posts under Uncategorized

Announcing Riemann’s Lens

Announcing my upcoming virtual art display/simulation:

I will be publishing this on the Steam store, as soon as I can navigate the reams of paperwork and options, and figure out how to box up my program with their SDK.

Explore a wormhole!

Riemann’s Lens simulates the non-euclidean geometry and strange visual effects associated with a Riemannian wormhole. This interactive virtual art display allows you to fly around and through the wormhole, and render simple scenery in the euclidean space on either end. You can also adjust the size and geometry of the wormhole.

The simulation uses a compute shader to perform noneuclidean raytracing, and relies on the graphics card to perform some heavy computations. It has been developed on a machine with a GeForce GTX 1650, and it manages 2ish fps. Expect some lag. (Unless you have an awe-inspiring graphics card: Then brag about it.)

After I navigate the process and have the application shipped, I will post more about the math and logic behind the wormholes, the raytracer, and how to navigate in higher-dimensional noneuclidean space.



Apparently some explorers from the Falklands have recently found the wreck of the “Endurance” somewhere on the Antarctc seafloor. It was Shackleton’s failed expedition intending to cross the Antarctic on dogsleds, which ended up marooned in the ice surrounding the continent.

I remember once reading Jules Verne’s “Mysterious Island”, and remarking that it was the “anti-Lord-of-the-Flies” – the contrast in the picture of what men are asserted to be, and what their potential is, was stark.

This struck me in a very similar way. And it must be men like these that served as the inspiration for that brighter idea of human potential. It’s an interesting tale: Here you have people in lethal dire straights, and they behave rationally, gallantly, and honorably. They save themselves by extreme competence and self control. There is good faith and good will by everyone involved.

It’s a bit of an antidote to the present.


Okay, so a few things:

1. “Disinformatsiya” is rancid totalitarian duck-speak from an empire that imploded because *everything about it was a lie*. Transliterating it into English does not make it fresh and wholesome. “Misinformation” as a criterion for deciding which heretics to assault is such an integral part of Western civilization that it’s only found in all the best parts, like the Dark Ages, or the Reign of Terror, or … well, you get the idea.

2. “Lockdowns” are not a legitimate function of any government of free citizens. Lockdowns are what prison guards do during a prison riot. Do you think you are our jailers? Are the inmates of “your democracy” getting a little too rambunctious for your delicate sensibilities?

Your self awareness might not have been properly screwed down at the factory, but can you even *hear* yourselves?!

Spoiler alert!: The side that is hysterically censoring things in a desperate attempt to keep people from meeting and talking with each other, the side that angrily denounces the horrifying prospect of thoughts being independently formed in uncontrolled minds, while the jenga tower of their radiant and unquestionable truth makes ominous groaning noises are …. wait for it … NOT the good guys.

At this point you can lose, or you can lose, or you can maybe rethink your allegiance to people who are only going to be spurred to ever more desperate acts of oppression and evil, because they are stuck in the same dilemma you are.

1. You can “win”: Let’s suppose that your allies can successfully stamp on the collective human face forever. Never-mind that most people are never going to break the way you want them to: There will be the omnipresent danger that somewhere the light of understanding will dawn in someone’s eyes. Will it be accompanied by gratitude for those who were desperately trying to stop it from happening? When your victorious prison guards throttle the last human being in the last lockdown in the last gulag, where will that leave you? Yay.

2. You can lose: What if history doesn’t end? The video is never going away. The pictures are never going away. There are too many cameras in too many hands, too many people writing to each other, too many diaries being recorded. You can frantically erase things on all the “platforms” you control, but you can’t stop every letter or burn every book. Some people still use email. Hell, some people still use snail mail. Despite your feverish efforts, people are having beers at bars again and *talking*. At some point people are going to look back at the age of lockdowns and wonder whether your name was on any of the proposals howling for concentration camps and persecution. If mankind has a future worth bothering about, how do you think the would be prison-guards of humanity will be remembered? Will anyone care about their social credit score?

3. You can decide to forfeit this false position, either out of self-preservation, or because you suddenly remembered any relevant excerpt from all of human history and realize this is not going to go anywhere good. Maybe you haven’t hurt anyone yet. Or if you have, maybe you haven’t by your actions or cruel inaction killed anyone yet. Can’t say the same thing for your allies. Maybe no one will ever have to know. It’s not too late to get off this sinking ship. The faster this falls apart, the faster we can repair the damage and go somewhere worthwhile.

Shell World

Megastructure for sale! Get yer sci-fi megastructure here! Any authors that want to play with this idea welcome.

This is a write-up of an interesting idea I had back in August 2020. It’s for a particular type of sci-fi megastructure which should be stable (at least to back-of-the-envelope calculations) and would make an interesting setting/location/super-architecture-style for any authors who are interested. Not practical to build anytime soon, but interesting.
I’m not sure if this is original or not (I haven’t looked very hard.) If it is, I’m staking my claim! Publish or perish!

Shellworld Writeup

The basic idea, as described in the document, is that for a thick enough, large enough shell of matter, the force of gravity can balance internal pressure. The radius divides out, so this structure can be built without tensile stress to arbitrarily large radii, allowing the construction of massive amounts of habitable volume.

(PS: after some comments with James Cambias, it turns out this idea may not be original to me. Darn.)

Interesting Reading

Some interesting things I’ve been reading this year:

The Wright Bros by David McCollough is an interesting biography of the inventors of controlled heavier-than-air flight. One fascinating part was a reference to a speech made by Wilbur Wright at the Western Society of Engineers.

Link to my copy of the speech: “Some Aeronautical Experiments”, Wilbur Wright, 1901:


Link to where I obtained it from: Link
Link to the biography: The Wright Brothers, David McCollough

This is one example of what a first rate mind approaching a problem looks like. Wilbur makes it clear that the principal difficulty that he and his brother were tackling at Kitty-Hawk was the problem of controlling the vehicle while in the air. They built up the knowledge to do so with an extensive series of glider experiments. The experiment-heavy, experience heavy and iterative nature of their self-directed program contrasts with other efforts to build flying machines at the time: A large upfront investment made in an expensive machine which promptly crashes.

While the Wright Bros faced some pretty stiff incredulity and cynicism, most of that cynicism came from the world of the press and humanities. There was a fairly serious and supportive community of engineers who were making efforts to tackle the problem of heavier-than-air flight. (The Dayton Daily news refused to acknowledge their accomplishments, even as they were doing laps around Huffman Prarie. It fell to a Kentucky almanac run by a beekeeper to provide their first publicity!)

Book Workbench Python Scripts

Link to the scripts

Book Dumping and Book Binding Scripts

Aaron M. Schinder

18 Mar 2021


These scripts are intended to dump image files from pdfs and bind image files into pdfs. I wrote these primarily to convert Archive.org pdfs from the highly compressed format they use to less compressed but more readable pdfs built from the images.

The various Linux pdf readers have difficulty unpacking archive.org books. It’s a known problem. (It takes a very long time to load pages in whatever format or scheme archive.org uses internally)

The idea here is that hard drive space is cheaper than time, especially the loading time for the pages which may make paging and skimming through a book untenable. Paging through images can be done almost as fast as flipping through a physical book, so it doesn’t impede using them in a similar manner.


These tools were written to work on Linux (I don’t know if they’ll choke on Windows or not – may require some fiddling.)

They require the imagemagick command line tools (convert). Imagemagick may need the settings adjusted in /etc to avoid running out of memory.

They require pdfinfo and pdfunite and pdfinfo utilities from the poppler package/library.


ams_dumplargepdf.py : Dumps a pdf to image files in a directory named after the pdf file.

ams_dumpallbooks.py : Iterates over all pdf files in the directory it is called in.

ams_bindbook.py : takes all the image files in a directory and creates pdf fragments in stages. The pdfunite is called to concatenate all the pdfs into a new bound pdf. (Warning, it will name the pdf the same as the directory name: shuffle the files around to avoid an overwrite.)

ams_bindallbooks.py : takes all the book image directories and makes pdfs from them.

February 2021 Machine Shop Adventures

I recently bought some stepper motors from Sparkfun. I have two others floating around somewhere – they are of the NEMA-17 type (which specifies the face and shaft dimensions and mounting holes.) Mine are m-3 instead of 4-40 mounting holes, but otherwise standard.

I’ve often longed to do something with these motors – to build tools which can build better tools. My initial attempts to build motion stages involved buying stock parts from McMaster and attempting to 3d print all the connecting parts with a Makerbot Replicator 2X. Unfortunately the 3d printer has only about 0.04 inch accuracy, which isn’t enough to make motion stages that won’t bind, even when just aligning steel rods.

In my quest to become able to build serious tools, I’ve acquired a machine shop. I’m still not sure quite how to “climb the tech tree” from poor tools to better ones (more accurate, more precise). How *did* we get from hand tools to the bridgeport? How do you make something more accurate with something less accurate?

(edit, in response to the comment below: Since trying to build my first stages, I have done a little research on some of the steps in this process. I think one of the first ones involved Maudsley in England creating a lead screw using a self-propelled inclined knife on a flat slide climbing against a brass-rod workpiece. Also the Whitworth grinding proceess (which I’ve used myself on 3 pieces of steel – incredibly tedious) to get flat planes. That gave him a master leadscrew which eventually gave him a lathe, which gave some degree of positioning accuracy. I’m not surprised to see interferometry in there. Still haven’t read up on how they managed squareness. I’ll have to watch more of Dan Gelbart’s videos, since he’s been through the process I’ll eventually want to go through.)

Anyway, step 1 would be to build some motion stages so that I can build a CNC thing. (I’m thinking small, high-RPM/low tool force carbide bit CNC mill or something…)

Pencil scribbles

I am not my grandfather. My grandfather could do beautifully fine hand-drawings with drafting tools. I’ve inherited this old map of his alma-mater, Tri-State College done by him during a course on engineering drawing (will include eventually). Thomas French, Engineering Drawing – it was tucked into his textbook.

Hand drawings are useful: They’re faster than CAD when you’re still trying to figure things out, and may be entirely sufficient to plan out a part. Here is that hand-drawing cleaned up and colorized for visual interest.

The big idea

Anyway, this was the plan. I ordered a bunch of stock parts from McMaster, I made one attempt last week to cut the dovetail slide from a piece of aluminum. I figured, aluminum is softer. I can practice on it without blowing up my tools. That worked until I attempted to use the dovetail cutter. Advancing about 50 thousandths per step (way too fast), without using adequate lubricant (Dad suggests WD-40 when cutting aluminum. *Not* when cutting steel – then it would carbonize and work-harden the part.), I ended up blowing up the dovetail cutter in my face.

Aluminum doorstop that also handily stabs you

I decided, since getting the part to that state took 5 hours, to bite the bullet and just do it in steel this time. 5 hours of end milling and a nautical ton (it’s an English unit, honest!) of chips later, I had the slide squared and the square-cuts done with nice surface finish. Can’t feel any roughness with my fingernail (the fingernail test).

Beautifully squared piece of steel, ready for wrecking

I painted some Dykem blue layout fluid on the corner in an attempt to see my cuts.

The wax goop on the tool was difficult to pry off. Tools are often dipped in this waxy crud to prevent corrosion. I managed to get it off by submerging the tool in a pot of boiling water – this worked and allowed me to easily remove the wax, which is important when attempting to get the tool into a precise starting position.

This shows the tool ready to cut. This time I was paranoid, listened very carefully to the horrible noises the cutter made as I advanced, and probably saved myself from a blowup at the very end. I advanced about 5 thousandths per step towards the end, and only about 0.2200 of my planned 0.2500. On the last cut the tool made a horrible racket on the last inch of the cut. On attempting to start the back-side, the tool wouldn’t cut at all. It had dulled itself fairly quickly.

It was a high-speed steel (as opposed to the cobalt steel) 45 degree, 1 3/8″ diameter dovetail cutter from McMaster Carr. (Not sure if I recommend them – they dull too fast.) I’m waiting on a new cutter to finish the job, and some carbide inserts for a 60 degree insert dovetail cutter from Dorian Tool by way of MSC.

One random trick that I had heard about watching youtube videos of people doing far more intricate things: Apparently when cutting steel, you can pay attention to the color of the chips. Straw-yellow means that the chips are getting somewhat hot as you are cutting. If they start turning blue, it means you are work-hardening the part and generating too much heat, and need to proceed (with more coolant, less agressively, at lower speeds).

South Bend Lathe Model SBL400 Parts List

I recently purchased a used metal lathe: A South Bend model SBL-400, from Jones Machinery in Cinncinatti.

Unfortunately, I did not have an opportunity to inspect the lathe very closely until now, and there are too many things wrong with it to make much use of it. It’s been used hard over the years, and the cross-slide skips. There’s some sort of collet holder wedged into the spindle and I’m not sure how to remove it. The foot-break won’t engage. Etc.

It’s a good model, but this one would be dangerous to attempt to operate, and I’d have to sink a lot of money into repair.

As part of the purchase, I bought a parts list that I couldn’t find anywhere online in digital form. Here is the parts list for anyone else out there lucky enough to have an SBL-400 in better working order:

SBL Parts List

Comment on James Cambias’s Blog

This isn’t entirely aligned with the topic of his post, but I saw something in the news about another SETI search coming up empty. I don’t think this indicates much about the absence of alien life in the universe, for the reasons in my comment:

One of the articles mentioning the seti survey, but not the original: https://www.nanowerk.com/news2/space/newsid=56088.php


(PS: James Cambias is the author of several science fiction novels that I’ve greatly enjoyed. A Darkling Sea is highly recommended. (One part great novel, one part novel-length panning of Star Trek’s prime directive.) Arkad’s World also makes some interesting points between the lines.)

My Post:

This doesn’t really address your post directly. I saw that article that floated recently about another SETI survey of some small fraction of the sky turning up empty again.

It seems popular to assume that if our radio waves could have traveled 100LY in principle, that we’re visible out to 100 LY, and that we could see aliens broadcasting like we do from such a distance. I think interstellar communication is more difficult, and necessarily more directional than most people assume.

The Galileo probe was an interplanetary spacecraft that operated around Jupiter. Galileo’s high gain antenna failed to deploy. Earth was trying to find the 20W omnidirectional low-gain antenna to talk to. It’s amazing that they could do it at all.

I was doing some physics doodling to get some numbers back into my head: I recall we managed to laboriously drag a 100 bit-per-second signal out of the noise floor from the Galileo probe at Jupiter. It was an S-band transmission, 20W, which amounts to 2,6E-24 W/m2 on average here at Earth. We had to coordinate several dishes with detectors cooled to 11K to obtain that signal, and we could only do it because we already knew Galileo was there and where to point the dishes!

Those big antenna dishes on planetary probes are not there for cosmetic reasons!

A 1GW omni-directional transmitter does roughly 100x worse at 5 LY, the approximate distance of our nearest-neighbor star. Aliens right next door couldn’t pick up a massive omnidirectional transmission, nor could we. Practical interstellar communication *must* be directional.

With a 1km dish in the X-band (8-12GHz) we can get gains of something like 2E9, by creating a beam that has a half-angle of 4.57E-5 radians. A 1GW sender could then be heard at “Galileo levels” at 25000 ly, or 1/4 distance across the galaxy. A 1kW sender can be heard at 25 LY at those extreme-limit levels, but the beam would only be about twice as wide as the orbit of pluto at that distance. For economical transmission powers, ranges are in the local-stellar neighborhood and necessarily pointed at specific stars. No one else could intercept that beam unless along a direct line of sight.

Your optics don’t have to be as extravagant in optical-laser wavelength ranges. An equivalent optic to that 1km dish for a 535nm laser is a 1.5cm lens: easily doable. You’d have to have a power of >800W to outshine the sun at a 1nm bandwidth, also doable with pulse lasers.

Anyway, I suppose what I’m saying is that it isn’t too surprising that a radio survey is coming up empty: Doesn’t indicate anything even if the galaxy is full of civilizations, other than that we’re not on the “point to” list. (The massive time disparity between “has radios and lasers” and “is moderately intelligent” that you discuss here seems more important.)

Comment on Isaac Arthur Video

On Isaac Arthurs thought provoking video on Consciousness and Identity:

My comment:

I dunno that you can place an upper bound on number of unique personalities. Configuration space blows up fast: For certain definitions, you must end up with more possibilities than raw materials. (Number of ways to arrange N balls is N!, which is > N when N>2). You can store N bits on your hard drive, but there are 2^N possible hard drive states.

Under one physics definition of identity, all electrons are the same. Drop the resolution, and you can say one bacterium is pretty much like all others sharing the DNA. A lot of lower animals seem like they approach life in much the same way and have more or less commensurate experiences. (Sphexic – insect like. All bees of a certain species will execute the same orbit when identifying something they want to land on.) The more complex the mind, the more space there is for these minds to be different.

Going to start posting some of this stuff here: I comment a lot on other people’s blogs, but my own blog ends up being pretty bare. If I spend all my time talking elsewhere, I won’t have a lot of content that accumulates here.